JPS62105167A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a fur inclination, also to execute exactly stirring action with a developer, and to execute the development of a high picture quality being free from an uneven development, by rotating a moving body and a fur brush in the forward direction at a contact position, and making a peripheral speed of the moving body higher than the peripheral speed of the fur brush. CONSTITUTION:A developing roller 22 being a moving body has a prescribed gap against a photosensitive drum 13, for instance, rotates counterclockwise, a fur brush 23 exists in a toner 19, slide-contacts the surface of the developing roller 22, and for instance, rotates clockwise. A fur 25 of the fur brush 23 being in a developing state is bent in one direction by an abutting part of a load of the toner 19 and a scraping plate 29, and thereafter, bent in the opposite direction by the next slide-contact part to the developing roller 22, since a peripheral speed of the developing roller 22 is higher than a peripheral speed of the fur brush 23. Therefore, it does not occur the the fur 25 of the fur brush 23 is always bent in one direction. In this way, the fur 25 of the fur brush 23 is prevented from its fur inclination, also a stirring action with the toner 19 is executed exactly, and a development of a high picture quality being free from an uneven development can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to copying machines, displays, etc. that apply electrophotography.
The present invention relates to a developing device in an image forming apparatus such as an electrostatic printer.

2. Description of the Related Art In recent years, developing devices using carrierless donors have been proposed for copying machines and the like in order to extend the life of the developer and simplify maintenance.

This developing device includes, for example, Japanese Unexamined Patent Publication No. 56-110963.
No. 2 is available, and its configuration is shown in Figure 2.

In FIG. 2, e is a photoreceptor, 7 is a developing roller made of a conductive urethane material that is in sliding contact with the photoreceptor 6, 8 is a conductive fur brush that is in sliding contact with the developing roller 7, and 9 is the fur brush 8 and the developing roller 7. 10 is a voltage divider for adjusting the voltage of the power supply 9, and 11 is a hopper containing toner 12. The toner 12 supplied from the hopper 11 to the fur brush 8 is triboelectrically charged by the fur brush 8, and then electrostatically deposited from the fur brush 8 onto the developing roller 7 by the direct current voltage of a power source 9 to be coated. Next, when the toner 12 on the developing roller 7 faces the electrostatic latent image on the photoreceptor, it flies and develops.

Problems to be Solved by the Invention In the developing method shown in FIG. 2, the bristles of the fur brush are in sliding contact with the developing roller. If the bristles are stiff, the sliding force of the bristles will be strong, causing toner filming on the surface of the developing roller and uneven development, so generally those with weak bristles are used. Further, when the peripheral speed of the fur brush is faster than the peripheral speed of the developing roller, the bristles of the fur brush are always bent in one direction by the load of toner in the hopper and the sliding contact portion of the developing roller. As a result, the bristles of the fur brush no longer come into sliding contact with the developing roller, and the agitation effect between the bristles of the fur brush and the toner is reduced, resulting in a low triboelectric charge amount of the toner, resulting in uneven development.

The present invention solves the conventional problems and provides a developing device with high image quality.

Means for Solving the Problems The present invention provides a hopper containing a developer having an outlet, a movable body provided at the outlet for carrying the developer, and a position within the hopper that is in contact with the movable body. The movable body and the fur brush are rotated in the forward direction at the contact position, and the circumferential speed of the movable body is made faster than the circumferential speed of the fur brush.

action The effect of this technical means is as follows.

In other words, as the fur brush rotates, the fur brush bristles
It is bent in one direction by the load of developer.

Next, the bristles bent in one direction are bent in the opposite direction at the sliding contact portion with the movable body because the circumferential speed of the movable body is faster than the circumferential speed of the fur brush. Therefore, the bristles of the fur brush are not always bent in one direction. Therefore, the bristles of the fur brush do not fall, and the stirring action with the developer is ensured, making it possible to develop high-quality images without uneven development.

Embodiment FIG. 1 shows a developing device according to an embodiment of the present invention, and is an example used in the developing process of a copying machine.

In FIG. 1, reference numeral 13 denotes a photosensitive drum which is a charge carrier having an electrostatic latent image, and is provided by coating a photosensitive material 16 such as zinc oxide, selenium, OPC, etc. on the surface of a base 14 of mulch, for example. It is something. Reference numeral 16 denotes a charger, which applies corona (negative in the case of zinc oxide and positive in the case of selenium) depending on the photosensitive material 15 of the photosensitive drum 13 by the first high-voltage DC power supply 17 to charge the photosensitive material 15 of the photosensitive drum 13. 15 is charged over the entire surface. Reference numeral 18 denotes an optical section that projects a patterned optical image onto the photosensitive drum 13 to form a latent image. 19 is an insulating toner which is a developer;
A hopper 2o has an outlet 21 and stores the toner 19. Reference numeral 22 denotes a developing roller which is a moving body, and is a metal roller made of, for example, SUS made of an electrically conductive material, or the like, and the surface of the roller is formed into an uneven shape. Further, the developing roller 22 is connected to the outlet 21.
The photosensitive drum 13 is provided at a position facing the photosensitive drum 13 with a certain gap therebetween, and is rotated, for example, in a counterclockwise direction.

Reference numeral 23 denotes a fur brush, in which conductive fiber bristles 26 of rayon containing carbon, for example, are implanted on the outer peripheral surface of a mandrel 24.

Further, the fur brush 23 is located within the toner 19 in the hopper, and is in sliding contact with the surface of the developing roller 22, and is rotated, for example, clockwise. Furthermore, the peripheral speed of the fur brush 23 is set to be slower than the peripheral speed of the developing roller 22. Reference numeral 26 denotes a second high-voltage DC power source serving as a voltage applying means, which applies a voltage between the developing roller 22 and the fur brush 23. .

A blade 27 is a regulating member for regulating the thickness of the toner, and is made of a material such as rubber, resin, or metal. The blade 27 is provided in sliding contact with the surface of the developing roller 22 downstream of the toner 19 portion of the hopper 20 and upstream of the developing section with respect to the rotating direction of the developing roller 22. A scraping plate 28 comes into contact with the bristles 25 of the fur brush 23 to equalize the amount of toner 19 within the bristles 25.

The operation of the developing device of one embodiment configured as described above will be described below.

In FIG. 1, zinc oxide is used as the photosensitive material 16 of the photosensitive drum 13 to make the operation easier to understand.

A negative corona is applied to the charger 16 by the first high-voltage DC power supply 17 to charge the entire surface of the photosensitive drum 13 with a negative charge. Next, the optical section 1 is placed on the negatively charged photosensitive drum 13.
8, a patterned light image is projected to form a latent image. During this time, the toner 19 in the hopper 20 is supplied into the bristles 25 by the rotation of the fur brush 23. Next, the excess toner 19 in the bristles 25 is scraped off by a scraping plate 29 and an appropriate amount is supplied. Further, the toner 19 is conveyed to a position facing the developing roller 22 by rotating the phage 2 230 times. The appropriate amount of supplied toner 19 is removed from the scraping plate 29. A positive charge is uniformly applied by the friction with the surface of the developing roller 22 and the agitation effect caused by the rotation of the fur brush 23. Next, a positive voltage is applied to the fur brush 23 side between the developing roller 22 and the fur brush 23 by the second high-voltage DC power supply 2e, and the surface of the developing roller 22 is coated with toner to a predetermined thickness or more. At this time, the thickness of the toner layer on the surface of the developing roller 22 varies beyond a predetermined toner layer thickness. Next, the developing roller 22 rotates, and the developing roller 22
The charged toner 19 on the surface is partially scraped off when it passes through the blade 28, and is regulated to a predetermined toner thickness.

Next, when the negatively charged latent image on the photosensitive drum 13 faces the positively charged toner 19 on the surface of the developing roller 22, the toner 19 flies to the photosensitive drum 13± and can be developed. In this developing state, the bristles 26 of the fur brush 23 are affected by the load of the toner 19 and the scraping plate 290.
After being bent in one direction at the contact portion, it is bent in the opposite direction at the next sliding contact portion with the developing roller 22 because the circumferential speed of the developing roller 22 is faster than the circumferential speed of the fur brush 23. Therefore, the bristles 25 of the fur brush 23 are not always bent in one direction. Therefore, the bristles 26 of the fur brush 23 do not fall, and the stirring action with the toner 19 is ensured, making it possible to develop high-quality images without uneven development. In the present invention, the blade 27 is provided in consideration of the density variation of the bristles 25 of the fur brush 23, but the density variation of the bristles 26 does not occur.

If the specific resistance variation is small, even if the blade 27 is removed, a more uniform toner thickness can be formed on the developing roller 22, and the bristles 26 of the fur brush 23 will not fall.

Effects of the Invention The present invention rotates the movable body and the fur brush in the forward direction at the contact position between the movable body and the fur brush, and makes the circumferential speed of the movable body faster than the circumferential speed of the fur brush.
It can prevent the hairs of the fur brush from falling down.

Therefore, the bristles of the fur brush are always in the initial state and the developer can be uniformly charged. Therefore, a stable thin layer of developer can always be coated on the moving body, and stable development with high image quality can be achieved.

[Brief explanation of drawings]

FIG. 1 is a sectional side view of a main part of a developing device according to an embodiment of the present invention, and FIG. 2 is a sectional side view of a main part of a conventional developing device using a one-component developer. 19...Developer, 2o...Hopper, 2
1. exit, 22... moving object, 23...
fur brush. Name of agent: Patent attorney Toshio Nakao and 1 other persontq
-～-Injured Robbery I z3-1-Far Furashi

Claims (1)

[Claims] The hopper includes a hopper containing a developer and has an outlet, a movable body provided at the outlet for carrying the developer, and a fur brush provided in the hopper at a position in contact with the movable body, A developing device that rotates a movable body and a fur brush in a forward direction at a contact position and makes the circumferential speed of the movable body faster than the circumferential speed of the fur brush.